Arc-suppressing device



Aug. 10 1926.

O. H. ESCHHOLZ ARC SUPPRESSING DEVICE Filed Nov. 29, 1920 INVENTOR 0lt011 Exbbolz ATTORNEY WITNESSES:

Patented Aug. 10, 1926.

UNITED STATES PATENT OFFICE.

OTTO H. ESCHHOLZ, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

ARC-SUPPRESSING DEVICE.

Application filed November 29, 1920. Serial No. 427,061.

My invention relates to circuit-interrupting, systems and it has for oneof its objects to reduce the arcinginormally-attending the opening of acircuit interrupter.

Another object of my invention is to pro"-' vide a circuit-interruptings stem that shall comprise an electric valve 0 such characteristics andso related to the interrupter as to shunt the circuit current around theinterrupter when the latter is opened and to automatically build upresistance to the current until the flow of the latter is stopped.

In practicing my invention, ,1 provide an electric valve, preferably ofthe so-called hot-cathode type, of which the cathode circuit isconnected in shunt to the circuit and in which the anode circuit, takenin conjunction with the cathode circuit, forms a local series-parallelsystem connected in shunt to an interrupter. When the interrupter isopened, in response to short-circuit or predetermined overloadconditions, the main circuit current is shunted through the anodecircuit and there will be substantially no arcing at the interruptercontact members. The arrangement is such that, after the opening of theinterrupter and when the main-circuit current is passing through thevalve, a rapid diminution of the excitation of the cathode will cool thelatter to a temperature below that necessary forelectron emission. Thevalve will, thus, function to rapidly, and by graduated amounts, insertresistance from a valve substantially equal to the resistance of thecircuit to be interrupted to infinite resistance preventing the passageof current.

Figure '1 of the accompanying drawings is a diagrammatic view of acircuit-interrupting system embodying my invention and Figs. 2, 3 and 4'are similar views of moditied t'orms thereof.

In all of the figures, a main circuit interrupter 1, connected to asuitable supply gndga. resetting spring ll for the core mem- As shown inFig. 1, an electric valve 12 comprises a cathode 13 that is connected,at one side through an adjustable resistor 14 and a reactor 15, to themain circuit 2 and,

at the other side, through a'conductor 16,

also to the main circuit 2 but with a device 17, that may be a resistoror a reactor, in the circuit 2 between the cathode terminals. The anode18 of the valve 12 is connected, by a conductor 19, to the main circuit2 at a side of the interrupter 1 opposite to that to which the conductor16 is connected to the circuit 2.

The cathode circuit is adapted to receive local current from the maincircuit by reason of the drop of potential across the device 17. Thislocal current may be so chosen, or adjusted by the resistor 14,as torender the cathode 13 normally relatively cold or to malntain it at apredetermined relatively high temperature. Whether the cathode shall bemaintained at one temperature or another depends upon thecharacteristics of the circuit 2, and while it is desirable to normallymaintain the cathode relatively cool to conserve the life thereof,certain advantages will obtain by normally maintaining it relativelyhot. One of these advantages is that it is easier to raise the oathodetemperature from a relatively high value that may be, at the same time,just below that required to give the required electron emission, to thatat which the main circuit current will freely traverse the valve,

the anode 18, the electron-filled space be-' tween the anode l8 and thecathode 13, and the conductor 16. The sudden rise of the main circuitcurrent, just previous to the opening ofthe interrupter 2, will so heatthe cathode 13 as to cause the emission of a sufficient quantity ofelectrons to convey the shunted current through the valve withsubstantially no opposition.

\Vhen the interrupter 2 opens, the cathode 13, being deprived of itssource of energy, will quickly, but by graduated amounts, be so cooledas to gradually diminish its electron emission. This action will, thus,automatically buildup resistance to the main circuit current until thelatter ceases to flow. The reactor 15 is adapted to cause the localcathode current, and therefore the cathode temperature, to lagsufiiciently to assure the complete transfer of the line current fromthe breaker to the valve circuit.

As shown in Fig. 2, the arrangement is substantially the same as thatshown in Fig. 1, with the exception that the local catho e circuit maybe mechanically interrupted, by a switch 20, at the end of apredetermined interval of time after the opening of the interrupter 1.The switch 20 may comprise a stationary contact member 21- and a pivotedswitch arm 22 that is biased toward the closed osition, by a spring 23,and is provided with a projection 24 for cooperation with a projection25 carried by the movable parts of the interrupter 1.

As shown in Fig. 3, a battery 26, that takes the place of the device 17in the forms shown in Figs. 1 and 2, is provided for enerizing thecathode 18. Also, as shown in ig. 3, the resistor 1 1 is renderedautomatically adjustable by the co-operation of terminal taps 27 thereofwith a switch arm 28 that is biased toward one position by a spring 29and actuated toward another position by an electromagnet 30 having acore member 31 and a coil 32 connected to the circuit 2.

Vi hile all of the above shown and described forms of my invention arereadily adaptable for either alternating or directcurrent circuits, theform shown in Fig. 4.- is particularly adapted for an alternatingcurrentcircuit.

As shown in Fig. 4:, the system is substantially a combination of thesystems shown in Figs. 1 and 3, it having two of the valves 12 eachsimilarly connected on opposite sides of the interrupter 2. Since thevalves 12 are asymmetric, the arrangement shown in Fig. 4-, will ensurethe interruption of the main circuit current in the one or the other ofthe valves during the first halt cycle of the alternating-current wave.

While 1 have shown and described particular "forms of my invention,changes may be effected therein without departing from the spirit andscope thereof, as set forth in the appended claims.

' claim as my invention A circuitintcrrupting s 'stem compriscircuit, acircuit interrupter, an electron emission valve connected in shunt tothe interrupter and means effective only upon an overload in the circuitfor energizing the valve.

2. A circuit-interrupting system comprising a circuit, a circuitinterrupter, an electron emission valve connected in shunt to theinterrupter and means for energizing and for radually changing theamount of energization of the valve.

3. A circuit-interrupting system comprising a circuit, a circuitinterrupter, an electron emission valve connected in shunt to theinterrupter and automatically actuable means for energizing the valveonly upon the occurrence of an abnormal condition in the circuit.

4. A circuit-interrupting system comprising a circuit, a circuitinterrupter, an electron emission valve connected in shunt to theinterrupter, and automatically actuable means for energizing and forcontrolling the amount of energization of the valve.

5. A circuit-interrupting system comprising acircuit, andelectron-emitting means connected thereto and adapted to interrupt thecircuit at the end of a predetermined interval of time after theoccurrence of predetermined conditions therein.

6. A circuit-interrupting system comprising a circuit interrupter, andan electron emission valve adapted to conduct the circuit current afterthe opening of the interrupter and to interrupt the current at the endof a predetermined time interval.

7 A circuit-interrupting system, comprisin na circuit interrupter, andan electric valve connected in shunt to the interrupter and having acathode circuit connected in parallel wlth a portion of the circuit atone side of the interrupter. 8. A circuit-interrupting system compris-111 a circuit lDtGII'UDtGI, and an electric valve having a cathodecircuit connected in shunt to a portion of the circuit, and an anodecircuit that, with the cathode circuit, constitutes a series-parallelshunt circuit, the anode and cathode circuits each being conhected atone end to opposite sides of the interrupter.

9. In an electric circuit, the combination with a circuit interrupter,of a hot-cathode valve connected across the interrupter, and meansresponsive to the circuit conditions for controlling the cathode of thevalve.

10. In an electric circuit, the combination with a circuit interrupter,of a hot-cathode valve connected across the interrupter, and meansresponsive to the circuit conditions for controlling the heating of thecathode of the valve. 7

11. In an electric circuit, the combination with a circuit interrupter,of a hot-cathode valve connected across the interrupter, and

means responsive to the current traversing the circuit for controllingthe heating of the cathode of the valve.

12. A circuit-interrupting system comprising a circuit, anelectron-emitting means connected thereto, means governed bypredetermined conditions in the circuit for rendering the electron meanseffective to maintain the circuit, and means for controlling the periodof time during which the electron 10 means remains effective.

In testimony whereof, I have hereunto subscribed my name this 17th dayof N0- veinher, 1920.

' OTTO H. ESCHHOLZ.

